Automatic grinding machine for spiral drills



Jan. 27,

Filed Feb,

gli 6 22 1959 H. `s. slEMsl-:N r-:T AL

AUTOMATIC CRINDING MACHINE FOR SPIRAL DRILLS 6 Sheets-Sheet;

Jan- 27, 1959 H. s. slEMsEN l ETAL 2,870,579

AUTOMATIC RINDING MACHINE FOR SPIRAL DRILLS Filed Feb. 28, 1955 6 Sheets-Sheerl 2 NM Q;

Jan. 27, 1959 H. s. IEMsEN ET AL 2,870,579

AUTOMATIC GRINDING MACHINE FOR SPIRAL DRILLS Jan. 27, 1959 vH. s. slEMsEN ET AL AUTOMATIC GRINDING MACHINE Foa SPIRAL DRILLs 6 Sheets-Sheet 4 Filed Feb. 28, 1955 Jfeizze Ja'e. BYM GCE- parz deg;

Jan. 27, 1959 H. s. slEMsEN ET AL AUTOMATIC GRINDING MACHINE FOR SPIRAL DRILLS I Filed Feb. 28, 1955v 6 sheets-sheet 5 v Jan. 27, 1959 H. s .VslEMsEN ETAL v2,870,579

AUTOMATIC GRINDING MACHINE Foa SPIRAL DR'ILLS Filed Feb. 2a, 1955 e sheets-sheet e zow P19555 wPE AIR To sico/VD marx Pos//o/v Low'PRrssu/PE H AIR TO DR lLl` BY (FMG. d@

United States Patent O AUTOMATIC GRINDING MACHINE FOR SPIRAL DRILLS Henry S. Siemseu and Kenneth E. Foote, Los Angeles, Calif.

Application February 28, 1955, Serial No. 490,772

8 Claims. (Cl. 51-94) v This invention relates to an automatic grinding machine for the points of spiral drills. This invention relates'to similar subject matter and is an improvement upon the invention set forth in our co-pending application, Serial No. 367,517, iiled July 13, 1953, now Patent No. 2,815,610, dated December l0, 1957.

A large number of spiral drills are used in various manufacturing industries. These drills become dull through use, requiring that their points be sharpened. In the past, this sharpening has been done by hand, requiring the services and skill of a trained operator. ltV is an object of our invention to provide a machine which will automatically perform this sharpening operation and produce results equal to or better than those obtained by manual grinding. Our machine can be operated by an unskilled person with substantially no training whatsoever, since the operation of the machine is entirely automatic except for insertion and removal of the drills.

The result is that an unskilled person can sharpen more drills with our device than a skilled operator by manual operation, and each drill is sharpened uniformly and perfectly, eliminating all human error, ineiciency and inaccuracy.

It is more particularly an object of our invention to provide such a device in which the method of grinding simulates that used in manual grinding, namely moving the drill vertically past the grinding wheel. With our device, the drill is held and moved toward the grinding wheel. The drill is moved vertically to grind one side and is then rotated 180 and moved vertically to grind the other side. The time required for grinding each drill is reduced to substantially a minimum, while the grinding operation itself duplicates that of a skilled manual operator.

It is among the further objects of our invention to provide such a device in which the grinding of the drill, its rotational orientation, its positioning, the movement of the drill to, from and through the grinding operation and the release of the drill are all efciently and automatically accomplished.

It is also among the objects of our invention to provide an improved means for grinding, improved means for holding, positioning, and release of the drill and to provide numerous other advantages of construction and operation. Because of the complex nature of our device, further aims and objects of the invention will be more fully understood by reference to the accompanying drawings and detailed explanation of our invention. Our invention accordingly comprises such other objects, advantages and capabilities as will later more fully appear and which are inherently possessed by our invention.

While we have shown on the accompanying drawings a preferred embodiment of our invention, it should be understood that the same is susceptible of modification and change without departing from the spirit of our invention.

Referring to the drawings,

Fig. 1 is a front elevational view of our device, with the bottom of the base being cut olf;

Fig. 2 is a side elevational view of the same, taken on the left side of Fig. 1;

Fig. 3 is a fragmentary top plan view of the grinding mechanism;

Fig. 4 is a vertical sectional view of the clutch taken on line 4 4 of Fig. 3;

Fig. 5 is a detailed elevational view partly in section of the drill stabilizer;

Fig. 6 is a fragmentary sectional view taken on line 6-6 of Fig. 3;

Fig. 7 is a fragmentary side elevational view of the chuck;

Fig. 8 is a front elevational view of the drill point and drill locator;

Fig. 9 is a front elevational view partly in section of the chuck and two cylinders;

Fig. 10 is a fragmentary plan view'of the chuck;

Fig. 11 is a vertical sectional view of the chuck taken on line 11-11 of Fig. 9;

Fig. 12 is an enlarged front view of the chuck shown partly in section;

Fig. 13 is a rear elevational view of the chuck;

Fig. 14 is a schematic diagram of the electronic and solenoid controls.

A preferred embodiment which has been selected to illustrate my invention comprises a grinding machine 10 having a base 12 within which there are mounted various control means as will be more fully described later. Upon this base 12 there is located a vertical support 14 to the top of which there are secured bearings 16 which carry a shaft 18 which conveys power from a motor 2@ to a grinding wheel or disc 22. Belt means k24 are used to connect the shaft 18 with the motor 20. The motor 2li is attached to the base 12.

Upon the vertical support 14 there are mounted guide rails 26 which are engaged by complementary shaped guides 30 formed upon a table 32 in such a manner that table 32 may be moved vertically with respect to the vertical support 14 when a hand wheel 34 is turned so as to rotate a shaft 36 and an attached beveled gear 38. The beveled gear 38 is positioned so'as to co-act with another beveled gear 40 mounted upon the top of a threaded shaft 42projecting upwardly from the base 12 through a conventional threaded bearing 44. The bottom of the beveled gear 40 is supported upon an appropriate conventional cross brace 46 forming a part of the table 32.

Upon the table 32 there are mounted guide rails 48 which are engaged by complementary shaped guides 50 formed upon a first carriage 52 so that the `first carriage 52 may be moved with respect to the table 32 in a direction at a right angle to the direction of movement of table 32. The actual movement of the rst carriage S2 may be carried out through rotation of a hand wheel 54 which is attached to a threaded shaft 56 located within bearings 58 formed upon the table 32. The shaft -56 is in engagement with an appropriate threaded member (not shown) secured between the iirst carriage 52 and the table 32. i

Upon the first carriage 52 there is mounted a second carriage 6i? through the use of guide means 62 similar to the guide rails 26 and 48 previously described. These guide means 62 are engaged by complementary shaped guides 64 formed upon lthe second carriage 60 so that as a threaded shaft 66 is turned through the use-of a hand wheel 63, the threaded shaft 66 moves with respect to an appropriate threaded member (not shown) mounted upon the first carriage 52 so that the position of the second carriage 60 is adjusted in any desired manner.

It will be realized from the foregoing description that ast-0,519

the secondcarriage'tl moves Vin a direction at right angles to the direction of travel of both the table 32 and the first carriage 52. lt will 4be further realized that the preciseimeans by ywhich the table 32 and the rst and second carriage 52 and Gil are mounted are of a substantia'lly conventional nature known to the art and are similar to the guide means or ways used on any lathe or milling machine. The purpose of the table 32 and the first and second carriage 52 and oil is to provide a means whereby the position of the other mecb-nically operative parts hereinafter described may be readily adjusted'with'respect to the grinding disc 22 so as to obtain operation of the complete machine lll with any size drill, and with any size grinding disc.

Upon the top surface of the second carriage ther are located two parallel inverted T-shaped slots Til such as are manufactured by cutting with a Woodruff key cutter. On one side of the second carriage el) there is located a third slot 72 of the same category, the third slot 72 being parallel to the slots 70.

Upon the second carriage oil there is secured a bearing support`7f-l having upstanding ends 76, within which there are mounted bearings which carry a lirst shaft 8G in such a manner that this shaft Eil may be rotated during the operation of the machine lil. Bolts S2 engaging the slots 76 are employed in the location of the bearing support "i/l. Adjacent to the slot 72 a lever arm 8d is connected to an extremity of the shaft 3i). This lever arm 84 is in turn connected through the use of a pivot pin to a connecting rod 83 which projects from a hydraulic cylinder gli, the extremity of which remote from the pivot pin is attached to the second carriage 60 through the use of another pivot pin secured to a mounting bracket 94. This mounting bracket 9d is in turn secured to the slot '72 through the use of bolts 96.

Within the hydraulic cylinder 90 there is located a piston $8 having a conventional elastomeric (-ring seal N0 serving to seal the piston within the hydraulic cylinder 9i) so as to divide the cylinder into two parts, which are connected by hydraulic lines and to solenoid valves S-3 and 8 6, which are in turn connected to a suitable source of hydraulic pressure fluid, v-.fliich is preferably oil. Thus, as hydraulic fluid is introduced into the hydraulic cylinder 9i? through either of the hydraulic lines 192 and 104, the piston 93 is moved within the hydraulic cylinder 99, causing the connecting rod S3 to move out from the cylinder through an end opening ldd. This movement of the connecting rod t is transmitted through the lever arm 34 to the shaft 8d, causingr shaft to rotate within the bearings of bearing support '74.

The motion of the shaft Sil is in turn transmitted through parallel radial arms MPS attached to the shaft to cause the radial arms M8 to move with respect to the second carriage 6i). Bearing means il@ are aligned within the ends of the radial arms lll@ in order that a movable shaft i12 may be carried by the arms The movable shaft M2 is thus mounted parallel to the shaft in such a manner that it may be rotated aber the shaft Si) during the operation of the machine igidly secured to the movable shaft 312 are trunnion arms ll/l to the ends of which remote from the movable shaft ifi?, are attached appropriate trunnions llo. These trunnions .llo carry shafts 118 projecting from the opposite sides of a cylindrical housing l2@ forming a part or" chuck means hereinafter described, which hold a drill E22 in an operative position during the use of the machine ill.

The cylindrical housing i125 is formed so as to include a bearing groove i24- located internally thercon. This bearing groove is designed to form one part of. a bearing race for a plurality of ball bearings The other part of the race is constituted by a similar ly constructed groove E28 formed in a cylindrical flange i3d attached to an annular plate 132, which is in turn secured to a cylindrical -`member i3d on one side thereof through the use of bolts i3d. The same bolts 136 are employed to secure lll -lil

a second plate 133 to the other side of the Icylindrical member 134 in such a manner that a generally cylindrical flexible diaphragm Mtl formed out of an appropriate elastomeric material, such as rubber, neoprene or the like, is held with its edges positioned in recesses 142 located on the surface of the cylindrical member 134i adjacent to the plates i312 and 138. The diaphragm llt) is firmly held in this position so that escape of the fluid introduced between this diaphragm Mtl and the cylindrical member through a passage 144 formed in a wall of the cylindrical rnern erlld iS impossible. This passage M4 is connected through a hose 46 to a solenoid valve S-l, which is in turn connected to a suitable source of hydraulic or pneumatic pressure fluid, which is preferably high pressure air.

With this arrangement the hydraulic or pneumatic fluid may be introduced between the diaphragm Mtl and the cylindrical member 1345V in order to expand the diaphragm lill/l inwardly toward the center of the cylindrical member 3.3 in order to actuate movable jaw means located within the cylindrical member' i134. The movable jaw means comprises a first jaw E48 having a llat surface 15), within which there is formed a groove i552. This groove 52 is located generally parallel to the axis of the cylindrical member 'i3-fi and the cylindrical housing 125i immediately adjacent to this axis, and is intended to engage one side of the drill 122. Between generally parallel ends ld formed upon the lirst jaw laid is located a second jaw 256 having the shape of base illustrated in Fig. 12 of the drawings. The second jaw 1556 has sloping sides i523 so that during movement of the jaws and l56 there is substantially no danger of binding between the two jaws. The second jaw l also includes a liat surface which is located parallel to the at surface H50. This flat surface tot) includes a groove 3.62 corresponding generally to the groove 152 and serving the same purpose.

Coil springs i454 held within cavities M6 in the second jaw 156 bear against the first jaw Miel, normally forcing the two jaws ld and 156 away from one another. Thus, the two jaws are forced away from one another against the diaphragm i4@ so as to force fluid out of the lspace between the diaphragm Ml) and cylindrical member 134 when insufficient pressure to overcome the pressure of the springs B64 is supplied through the hose li.

Secured to the cylindrical housing l2@ is a supporting member S168 having formed therein an elongated passage i7@ which is open at its ends. To each of the ends of the passage Wil there are attached aligned cylinders V72 so that a rack W15 may be reciprocated between these two cylinders as pressure is applied to pistons 'l76 located within the cylinders lt72 and attached to the ends of the rack i743. Appropriate O-ring sealing means l are located within grooves lill) on the pistons l'76. rlhus, hydraulic fluid or air, preferably low pressure air, may he introduced into the ends il82 and i343 of the cylinders .477., remote from the housing l/lil through hoses lS and E38 so as to move the pistons l't and the attached rack iff/i with respect to the cylindrical housing lZtl. The hoses ld and li are attached to solenoid valves S-d and S--5, which control the flow of hydraulic fluid thereto from a suitable source of pressure supply.

The motion of the rack 174 is transmitted through a pinion gear 191) to the cylindrical member 134 attached to the pinion gear 1% through the use of the bolts 136 previously described. Thus during the operation of the machine lil the pistons 176 may be moved, causing movement of the rack 174 and rotation of the cylindrical member 134 and the other parts secured thereto. This construction represents a very eflicient chuck means which is useful during the operation of the grinding machine lll.

A drill locator 194 is mounted upon a bracket i916 which is secured to the second' carriage 60. The'purpose of the drill locator 194 is to orient the drill Iotationally so that the grinding operation is performed upon the proper surfaces thereof. The drill 122 is provided with one or more grooves 198. When the drill is inserted, it is rotated in a clock-wise direction by the operator of the machine until one of the grooves 198.

contacts the drill locator as shown in Fig. 8 of the drawings. The drill 122 is then properly oriented.

A drill stabilizer 200 is provided to prevent undesired vibration or movement of the point of the drill during the grinding operation. The drill stabilizer 200 projects at a right angle from the shaft 202 of a cylinder 204. The cylinder 204 is mounted upon a bracket 206 which is attached to the second carriage 60, land includes a piston 208 which is attached to the shaft 202 within the cylinder 204. The piston 208 is normally held by a coil spring 210 so that the shaft 202 is withdrawn into the cylinder 204.

A hose 212 is connected at one end to the end of the cylinder 204 remote from the drill stabilizer 200 and at its opposite end to a solenoid S2, which is in turn connected to la suitable source of hydraulic pressure Huid, which is preferably-low pressure air. The drill stabilizer 200 is brought into operation by hydraulic tluid being introduced into the cylinder 204 through the hose 212, forcing the piston 208 against the pressure of the coil spring 210 to move the shaft 202 a sufficient amount to hold the `drill stabilizer 200 against the drill 122.

The side of the drill 122 opposite from the drill stabilizer 200 bears against yan arcuate shaped support 214, the positioning of which is determined by a set screw 216. A mounting bracket 218 for the support 214 is attached to the cylindrical housing 120.

In order to guide the movement of the drill during the grinding operation, a guide means 222 is provided (Fig. 2), which is mounted with the use of bolts upon an appropriate bracket which is attached to the second carriage 60. The guide means 222 is provided with an arcuate cam surface 224 which corresponds to the surface which it is desired to place upon the point of the drill 122. A small wheel 220 is rotatably mounted on one of the shafts 118 and rotatably bears against the cam surface 224.

In operation, the wheel 220 travels up and down the cam surface 224 as the trunnion arms 114 move the trunnions 116. This results in an arcuate point being ground on the drill 122, which point is substantially identical with the point which would be ground by a skilled manual operator. y A pair of adjustable bolts 230 and 232 are mounted upon the second carriage 60 to act as stop means to limit the movement of the radial arms 108. This might result in damage if means were not provided to compensate for unnecessary movement of the piston 98 within the hydraulic cylinder 90. Such means are also a safety precaution in case something should become caught in the machine 10. Such means preferably comprise a friction clutch 236 as shown in Fig. 4 of the drawings. The clutch 236 is used to attach the lever arm 84 to the shaft 80 and comprises two rubber discs 238 which surround the shaft 80 on both sides of the lever arm 84. One of the discs 238 is held within a 'cup-shaped member 240 which is rigidly secured to the shaft 80. The other disc 238 is held in a similarly shaped member 242, which is merely positioned around the `shaft 80 so as to be forced against the lever arm 84 and the cup-shaped member 240. through the use of a coil 4spring 244, which is secured under tension to the shaft 80 by means of a bolt attached to the end of the shaft 80.

The operation of the .machine 10 is controlled by six solenoid valves S-1 through S-6, which are mounted in the base 12 asshown in Fig. l of the drawings. The solenoid valves are of conventional manufacture and are preferably of the type manufactured by Automatic Switch Co., Orange, New Jersey, and identified by them as Bulletin 8314, Three-Way Valves. rIlle solenoid valves are connected to the hoses set forth above and to suitable sources of hydraulic pressure uid. The movement of the uid through the hoses is controlled by the operation of the solenoids and by the resilient means bearing against the pistons. The hydraulic fluid used may be oil, high pressure air or low pressure air, and the term hydraulic as used in the specification and claims includes all types of hydraulic and pneumatic uids. The operation of the solenoid valves is controlled by electronic circuits.

Referring to Fig. 14 of the drawings, the electronic control system comprises three R-C timing circuits which control the operation of the solenoids through the opening and closing of relay contacts which control the electrical circuits to the solenoids.

It will be noted that each of the three tubes has its cathode either open or connected to the ground side of the circuit. When the cathode is open, the cathode and control grid act as a diode, causing some current to ow through the resistor and condenser which are connected in parallel in the control grid circuit of each tube. This current flow causes a negative charge to accumulate on the control grid side of the condenser, biasing the tube past cut-oi. When the cathode is connected to ground, current will not ow through the plate circuit until the charge on the condenser passes off through the resistors which are in series and parallel with it.

A cycle of operation begins with the insertion of a drill 122 into the grooves 152 and 162 of the chuck. The drill is rotated until its Igroove 198 contacts the drill locator 194 to properly orient the drill. The movable jaw means are then automatically closed to grip the ldrill 122 firmly between the jaws 148 and 156. This movement starts the cycle and is caused by the flowing of current through tube V-1, which current ow voccurs when the cathode is connected to ground through the normally closed contact of relay R-3 and the condenser in its control grid circuit as discharged through its associated resistors. When current ows through tube V-l, it operates relay R-l to close its normally open contact.

The closing of this contact of relay R-l acts to connect the cathode of the second tube V-Z to ground, so that this tube will start to conduct as soon as the condenser in its control grid circuit is discharged through its associated resistors. The closing of this contact also closes a circuit to operate solenoid S-l, causing high pressure air to move through the hose 146 and passage 144 to exert pressure on the diaphragm 140 and move the jaws 148 and 156 of the chuck on the drill which has been inserted therein. The closing of this contact also closes a circuit through the normally closed contact of relay R-2 to operate the grind relay R-4. The coil of the grind relay R-4 has a condenser in parallel with it which acts as a time delay to delay the closing of the relay contacts and thus delay the drill stabilizer and grinding movements of the machine until after the chuck has been closed.

The closing of the normally open contacts of the grind relay R--4 after this time delay results in the operation of solenoid S-2 to cause high pressure air to move into the cylinder 204 through the hose 212, forcing the piston 208 to move the drill stabilizer 200 against the drill 122. At the same time, the solenoid S3 is energized to cause oil to move through the hydraulic lineltl?. to move a piston 98 within cylinder 90 away from the mounting bracket 94. This in turn moves the connecting rod 88, and this motion causes the lever arm 84 to move, with resultant rotation of the shaft about its own axis. This rotation is transmitted through the radial arms 108, resulting in the trunnion arms 114 being moved from the initial position shown in Fig. 6 of the drawings to the position shown in Fig. 7.

During this movement, one side of the point 0f the drill 122 is brought into grinding engagement with the grinding wheel 22 and is moved upwardly past the grinding wheel until the drill T122 is again out of engagement therewith. This movement, being partially controlled by the arcuate cam surface 2,24, imparts a curved surface to the point of the drill 122.

When the grinding of one side ot the drill been completed, the drill stabilizer must drawn from contact with the drill E22.

lne must also be rotated through an angle ol ldil" first index position in which it was ground to the index position for the second grinding operation.

This occurs when the condenser in the control grid circuit of tube V-I?. discharges and current llo-.rs through the plate circuit of tube V-Z. This operates relay R-Z to close its normally open Contact and open its normally closed Contact. The closing of the normally open coutact of relay ,l-2 closes a circuit through the coil of the index latching relay R-S. This reverses the contacts of relay R-S, opening the circuit to solenoid S-f and closing the circuit to solenoid S-5.

Hydraulic uid from solenoid S-5 is introduced through the hose It to move the rack 74 within the elongated passage lli, causing the pinion gear i9@ of the cylindrical member 'i3d to rotate i813" from the initial position. As this is done, the drill r7.2 is also rotated lSOU. Relay l-S is a latching relay, so that its movable contact arm stays in either position until the coil of the relay is energized, at which time it moves to the opposite position and stays there until the coil is again energized. The chuck will thus stay in the second index position until the index iatching relay t-: 3 again energized during the middle of the next cycle or. operation, at which time solenoid S-S will be cle-energized and solenoid S-l energized to move the chuck to its lirst index position.

The opening of the normally closed contact ot R-2 also opens the circuit to the drill stabilizer noid S-Z, so that the coil spring 2li) causes the drill stabilizer 2li@ to retract. The circuit to the drill stabilizer solenoid S-2 is not completed again until the grind relay R-A. is tie-energized to close the drill stabilizer solenoid Circuit through its normally closed contacts and through the normally open contact of relay lio-2.

The opening ci the normally closed Contact ot` relay R-2 also opens the circuit through the coil ol the grind relay RJZ. The release of its contacts is, however, delayed by the condenser which is in parallel with the coil. This delays the second grinding and drill stabilizing rn ove. ments until alter the index reversal has taken place. The opening of relay R-d also opens the circuit through the oil solenoid S-3 and closes the circuit through the oil solenoid S-d to move the machine through its second grinding operation.

During the second grinding operation. hydraulic fluid is introduced through the hydraulic line lud, causing the piston to be moved within the cylinder @is back to its initial position. This will cause corresponding rotation and movement of ll of the movable partsY in the exact reverse of the movement previously described and will return the drill 22 vertically downwardly from the position shown in Fig. 7 to the position shown in Fig. 6 of the drawings.

Fl'he closing of the normally open contact of relay l-2 also connects cathode of tube wf-3 to ground so that this tube will start to conduct as soon as the condenser in its control grid circuit is sufficiently discharged, lt vill be noted, however, that there is a condenser in parallel with the coil of relay R-3. This condenser acts a time delay to prevent the immediate closing of relay R-S. 'When relay R-S is energized to open its normally 'closed Contact, it opens the cathode circuit of tube V-l, stopping this tube from conducting and returning the contact ot its relay lll to its normally open position. This relay soleopens the circuit to solenoid .S-l to permit coil springs ile-i to move the jaws 143 and l5@ apart and release the drill from the chuck. This also opens the cathode circuit of tube V4, so that this tube stops conducting and the contacts of its relay l-2 return to normal position. The opening ot' relay R-Z operates the grind relay RJS utter a time delay caused by the condenser in parallel with its coil. The opening of relay R-Z also opens the cathode c of tube V-S, causing its relay R-S to open alter a time delay caused by the condenser' in parallel with its coil. During this time delay, the drill is released from the chuck and another drill is inserted. "'v'hen relay RHS opens, it closes the cathode circuit of tube V-l to start another cycle of operation.

While our machine is particularly adapted for grinding spiral drills, it can also be used for grinding points on other types of drills or for `other grinding operations. A plurality of toggle switches are provided on the base l2 for controlling the various electrical circuits and other suitable switches may be provided as indicated in Fig. 14. in use, one electric timing control circuit as shown in Fig. t4 can be used to control the operation of a large number ot solenoids and machines.

The drill locator 191i is also provided with a small block which is attached thereto and which extends into the path of the drill UZ to act as a stop to limit the forward movement of the drill 122.

lt should be noted that because the 'Flutes of the drill '$22 are disposed horizontally instead of vertically with respect to the grinding drill 122, the grinding lines extend at a right angle to the cutting edge instead of parallel thereto. This provides a better cutting edge, which is less likely to become faulty due to irregularities which inevitably occur in the grinding operation.

The duration of. the various timing intervals of the machine can be varied as desired by manual adjustment of the variable resistors to which the resistor condenser timers are connected, as indicated in Fig. 14 of the drawings.

lt will be noted that our machine operates at substantially the maximum possible speed. This is important, since it results in greater output per hour of operation, thus increasing the profit increment resulting from operation ofthe machine.

We claim:

l. A device lor grinding the points ol drills comprising a carriage, bearing means mounted on said carriage, a first shalt rotatably mounted within said bearing means, radial arms rigidly secured to said rst shaft, a second shaft mounted on said radial arms at a point remote from said first shaft, trunnion arms rigidly secured to said second shaft, trunnion means attached to said vtrunnion arms, a chuck having shafts projecting therefrom, said shafts being held within said trunnion means, a Vlever arm connected at one end thereof to said rst shaft, a piston connected at one end thereof to the opposite end of said lever arm, the opposite end of said piston being reciprocally mounted in a cylinder, a rotatable grinding wheel mounted adjacent to said carriage, a pair of inlets at the opposite ends of said cylinder, pneumatic means including valves to control fluid supplied under pressure to said cylinder-throughsaidinlets to reciprocate said piston in either direction and provide vertical upward and downward movement of said chuck with respect to said grinding wheel, a cylindrical member rotatably mounted within said chuck, a resilient cylindrical diaphragm disposed within said cylindrical member, means securing the edges of said diaphragm to said cylindrical member, movable vjaw means for gripping the endof a drill disposed within said flexible diaphragm, pneumatic means including valves to control fluid supplied under pressure between said resilient diaphragm and said cylindrical member to cause said resilient diaphragm to expand and move saidv movable jaw means to grip and release said drill, a pinion gear attached to said cylindrical member, an elongated rack in engagement with said pinion gear, said rack being mounted with its midportion slidably extending through an elongated passage adjacent to said pinion gear and its opposite ends comprising piston rods extending into one end of each of a pair of hollow cylinders disposed on the opposite ends of said elongated passage, pneumatic means including valves to control uid supplied under pressure to the opposite ends of said cylinders to reciprocate said rack and rotate said chuck, and means for automatically and sequentially closing the movable jaw means of said chuck to grip a drill, moving said chuck and drill vertically to bring one side of said drill into grinding contact with said grinding wheel and past said grinding wheel and out of contact therewith, rotating said chuck and drill through an angle of 180 about the longitudinal axis of said drill, moving said chuck and drill vertically in the opposite direction to bring the opposite side of said drill into grinding contact with said grinding wheel and past said grinding wheel and out of contact therewith, and releasing said drill from said chuck.

2. The structure described in claim l and a stationary arcuate cam surface mounted on said carriage adjacent said trunnon arms, a cam follower carried by said trunnon arms and engaging said arcuate cam surface, and a pair of stop members carried by said carriage, one of said stop members limiting the upward movement of said first shaft and the other of said stop members limiting the downward movement of said first shaft, said stop members being adjustable to control the positioning of said first shaft so that said cam follower travels along different parts of said cam surface to change the radius on the drill being ground.

3. A device for grinding the points of drills comprising a basal supporting means, a movable member mounted on said supporting means for vertical movement with of inlets at the opposite ends of said cylinder, pneumatic l means including valves to control uid supplied under pressure to said cylinder through said inlets to reciprocate said piston in either direction and provide vertical upward and downward movement of said chuck with respect to said grinding wheel, a cylindrical member rotatably mounted within said chuck, a resilient cylindrical diaphragm disposed within said cylindrical member, means securing the edges of said diaphragm to said cylindrical member, movable jaw means for gripping the end of a drill disposed within said flexible diaphragm, pneumatic means including valves to control uid supplied under pressure between said resilient diaphragm and said cylindrical member to cause said resilient diaphragm to expand and move said movable jaw means to grip and release said drill, a pinion gear attached to said cylindrical member, an elongated rack in engagement with said pinion gear, said rack being mounted within its midportion slidably extending through an elongated passage adjacent to said pinion gear and its opposite ends cornprising piston rods extending into one end of each of a pair of hollow cylinders disposed on the opposite ends of said elongated passage, pneumatic means including valves to control fluid supplied under pressure to the opposite ends of said cylinders to reciprocate said rack and rotate said chuck, and means for automatically and sequentially closing the movable jaw means of said chuck to grip a drill, moving said chuck and drill vertically to bring one side of said drill into grinding contact with said grinding wheel and past said grinding wheel and out of contact therewith, rotating said chuck and drill through an angle of 180 about the longitudinal axis of said drill, moving said chuck and drill vertically in the opposite direction to bring the opposite side of said drill into grinding contact with said grinding wheel and past Said grinding wheel and out of contact therewith, and releasing said drillfrom saidchuck. i

4. A device for grinding the points of drills cornprising a basal supporting means, a movable member mounted on said supporting means for vertical movement with respect to a rotating grinding wheel, a chuck carried by said movable member, pneumatic'means including valves to control fluid supplied under pressure lto provide vertical upward and downward movement of said chuck with respect to said grinding wheel, a cylindrical member rotatably mounted within said chuck, a resilient cylindrical diaphragm disposed within said cylindrical member, means securing the edges of said diaphragm to said cylindrical member, movable jaw means yfor gripping the end of a drill disposed within said exible diaphragm, pneumatic means including valves to control lluid supplied under pressure between said resilient diaphragm and said cylindrical member to cause said resilient dia phragm tov expand and move said movable jaw means tol grip and release said drill, a pinion gear attached to said cylindrical member, an elongated rack in engagement with said pinion gear, said rack being'mounted with its midportion slidably extending through an elongated passage adjacent to said pinion gear and its opposite ends comprising piston rods extending into one end of each of a pair of hollow cylinders disposed on the opposite ends of said elongated passage, pneumatic means including valves to control uid supplied under pressure to the opposite ends of said cylinders to reciprocate said rack and rotate said chuck, and means for automatically and sequentially closing the movable jaw means of said chuck to grip a drill, moving said chuck and drill vertically to bring one side of said drill into grinding contact with said grinding wheel and past said grinding wheel and out of contact therewith, rotating said chuck and drill through an angle of 180 about the longitudinal axis of said drill, moving said chuck and drill vertically in the .opposite direction to bring the opposite side of said drill into grinding contactwith said grinding wheel and past said grinding wheel and out of contact therewith, and releasing said drill from said chuck.

5. The structure described in claim 4 and said movable jaw means comprising a stationary jaw disposed on one side of said cylindrical member, said stationary member having a triangular groove formed 'therein adjacent to the axis of said cylindrical member and a movable jaw disposed on the opposite side of said cylindrical member, said movable jaw having al triangular groove formed therein adjacent to the axis of said cylindrical mem-ber, said grooves being complementary to each other to form a substantially square opening, a passage disposed on the side of said cylindrical member remote from said movable jaw for introducing fluid between said cylindrical member and said resilient diaphragm whereby when said fluid is introduced, said resilient diaphragm causes said movable jaw to move toward said stationary jaw, said4 movable jaw having a pair of elongated spring receiving openings disposed therein on opposite sides of the axis of said cylindrical member, and a coil spring mounted in each of said openings, one end of said coil springs bearing against said movable jaw and the other end bearing against said stationary jaw to normally urge said movable jaw away from said stationary jaw.

6. A device for grinding the points of drills comprising a basal supporting means, a movable member mounted on said supporting means for vertical movement with respect to a rotating grinding wheel, a chuck carried by said movable member, pneumatic means including valves to control fluid supplied under pressure to provide vertical upward and downward movement of said chuck with respect to said grinding wheel, said chuck having movable jaw means for gripping the end of a drill, pneumatic means including valves to control uid supplied under pressure to move said movable jaw means to grip and release said drill, a pinion gear attached vto said cylindriill cal member, an elongated rack in engagement with said pinion gear, said rack being mounted with its midportion slidably extending through an elongated passage adjacent to said pinion gear and its opposite ends comprising piston rods extending into one end of each of a pair of hollow cylinders disposed on the opposite ends of said elongated passage, pneumatic means including valves to control fluid supplied under pressure to the opposite ends of said cylinders to reciprocate said rack and rotate said chuck, and means for automatically and sequentially closing the movable jaw means of said chuck to grip a drill, moving said chuck and drill vertically to bring one side of said drill into grinding contact with said grinding Wheel and past said grinding wheel and out of contact therewith, rotating said chuck and drill through an angle of 180 about the longitudinaly axis of said drill, moving said chuck and drill vertically in the opposite direction to bring the opposite side of said drill into grinding contact with said grinding wheel and past said grinding wheel and out of contact therewith, and releasing said drill from said chuck.

7. A device for grinding the points of drills comprising a basal supporting means, a movable member mounted on said supporting means for vertical movement with respect to a rotating grinding wheel, a chuck carried by said movable member, pneumatic means including valves to control fluid supplied under pressure to provide vertical upward and downward movement of said chuck with respect to said grinding wheel, a cylindrical member rotatably mounted within said chuck, a resilient cylindrical diaphragm disposed within said cylindrical member, means securing the edges of said diaphragm to said cylindrical member, movable jaw means for gripping the end of a drill disposed within said ilexible diaphragm, pneumatic means including valves to control uid supplied under pressure between said resilient diaphragm and said cylindrical member to cause said resilient diaphragm to expand and move said movable jaw means to grip and release said drill, pneumatic means including valves to control uid supplied under pressure to rotate said chuck, and means for automatically and sequentially closing the movable jaw means of said chuck to grip a drill, moving said chuck and drill vertically in one direction to bring one side of said drill into grinding contact with said grinding wheel and past said grinding wheel and out of contact therewith, rotating said chuck and drill through an angle of 180 about the longitudinal axis of said drill, moving said chuck and drill vertically in the opposite direction to bring the opposite side of said drill into grinding contact with said grinding wheel and past said grinding wheel and out of contact therewith, and releasing said drill from said chuck.

8. A device for grinding the points of drills comprising a basal supporting means, a movable member mounted on said supporting means for vertical movement with respect to a rotating grinding Wheel, a chuck carried by said movable member, pneumatic means including valves to control fluid supplied under pressure to provide vertical upward and downward movement of said chuck with respect to said grinding wheel, said chuck having movable jaw means for gripping the end of a drill, pneumatic means including valves to control uid supplied under pressure to move said movable jaw means to grip and release said drill, rack and pinion means secured to said chuck, pneumatic means including valves to control liuid supplied under pressure to reciprocate said rack and rotate said chuck, and means for automatically and sequentially closing the movable jaw means of said chuck to grip a drill, movingl said chuck and drill vertically to bring one side of said drill into grinding contact with said grinding wheel and past said grinding wheel and out of contact therewith, rotating said chuck and drill through an angle of about the longitudinal axis of said drill, moving said chuck and drill vertically in the opposite direction to bringv the opposite side of said drill into grinding contact with said grinding wheel and past said grinding wheel `and out of contact therewith, and releasing said drill from said chuck.

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